Recently, I finished a FEA model for a pressure vessel.  the solid model was developed by another engineer.  it had one very high stress location in an unexpected location.  the constraints he use to locate the parts i found unusual.  The pressure vessel had a bolt flat end cap on one end a weld head on the other.  The flat end cap was not constrained using the features in the welded housing.  The end cap was constrained using a part that would normally be installed later in the assembly process.  I would think it not make a difference.  The FEA modeler locates all the parts using connections, etc.  Has anyone an issue between constrains and connection causing high stress location?